Ocean Sciences Centre, Memorial University of Newfoundland, St. John's, NL, Canada A1C 5S7.
Gene. 2012 Nov 10;509(2):232-46. doi: 10.1016/j.gene.2012.08.017. Epub 2012 Aug 19.
Early life stage mortality is one of the problems faced by Atlantic cod aquaculture. However, our understanding of immunity in early life stage fish is still incomplete, and the information available is restricted to a few species. In the present work we investigated the expression of immune-relevant transcripts in Atlantic cod during early development. The transcripts subjected to QPCR analysis in the present study were previously identified as putative anti-viral or anti-bacterial genes in Atlantic cod using suppression subtractive hybridization (SSH) libraries, QPCR, and/or microarrays. Of the 11 genes involved in this study, only atf3, cxc chemokine and gaduscidin-1 were not detected at the transcript level in all developmental stages investigated from unfertilized egg to early larval stage. Adam22, hamp, il8, irf1, irf7, lgp2, sacsin, and stat1 transcripts were detected in unfertilized egg and 7h post-fertilization (~2-cell stage) embryos, showing maternal contribution of these immune-relevant transcripts to the early embryonic transcriptome. The Atlantic cod genes included in this study presented diverse transcript expression profiles throughout embryonic and early larval development. For example, adam22 and sacsin transcripts rose abruptly during blastula/gastrula stage and were then expressed at relatively high levels through subsequent embryonic and early larval developmental stages. A peak in irf1 and irf7 transcript expression during early segmentation suggests that these interferon pathway genes play developmental stage-specific roles during cod embryogenesis. Stat1 had increasing transcript expression throughout blastula/gastrula, segmentation, and early larval developmental stages. Atf3, cxc chemokine, gaduscidin-1, and il8 transcripts rose approximately 2-3 fold during hatching, supporting the hypothesis that there is preparation at the immune-relevant transcript expression level to deal with environmental pathogens that may be encountered during early larval development. The specific roles that interferon pathway and other immune-relevant genes play in early life stage cod, and the potential impact of their dynamic transcript expression on immune competence of Atlantic cod embryos and larvae, remain unclear and warrant further study.
早期生活阶段死亡率是大西洋鳕鱼养殖面临的问题之一。然而，我们对早期生活阶段鱼类免疫的理解仍然不完整，并且可用的信息仅限于少数几种鱼类。在本研究中，我们研究了大西洋鳕鱼在早期发育过程中免疫相关转录物的表达。本研究中进行 QPCR 分析的转录物是先前使用抑制性消减杂交（SSH）文库、QPCR 和/或微阵列在大西洋鳕鱼中鉴定为潜在抗病毒或抗细菌基因的。在所研究的 11 个基因中，在从未受精卵到早期幼虫阶段的所有发育阶段中，只有 atf3、cxc 趋化因子和 gaduscidin-1 在转录水平上未被检测到。Adam22、hamphamp、il8、irf1、irf7、lgp2、sacsin 和 stat1 转录物在未受精卵和受精后 7 小时（约 2 细胞阶段）胚胎中被检测到，表明这些免疫相关转录物的母体贡献到早期胚胎转录组中。本研究中包含的大西洋鳕鱼基因在整个胚胎和早期幼虫发育过程中呈现出不同的转录表达谱。例如，adam22 和 sacsin 转录物在原肠胚/囊胚阶段急剧上升，然后在随后的胚胎和早期幼虫发育阶段以相对较高的水平表达。在早期分节阶段 irf1 和 irf7 转录物表达峰值表明这些干扰素途径基因在鳕鱼胚胎发生过程中发挥特定发育阶段的作用。Stat1 在原肠胚/囊胚、分节和早期幼虫发育阶段的转录表达不断增加。Atf3、cxc 趋化因子、gaduscidin-1 和 il8 转录物在孵化时增加约 2-3 倍，支持免疫相关转录物表达水平有准备以应对早期幼虫发育过程中可能遇到的环境病原体的假说。干扰素途径和其他免疫相关基因在早期生活阶段鳕鱼中的具体作用，以及它们动态转录表达对大西洋鳕鱼胚胎和幼虫免疫能力的潜在影响，仍不清楚，值得进一步研究。
